Before he pulled the trigger, Lonnie Glasco had a chilling announcement. “Nobody's going to leave,” he told co-workers in a lounge at a downtown San Diego bus-maintenance depot yesterday.

Then Glasco, a veteran Metropolitan Transit System mechanic, went outside in the early morning darkness and gunned down two employees before police fatally shot him in the parking lot.

Glasco, 47, had suffered some losses in recent years – first his marriage, then the house near Alpine that he saw as an escape from urban aggravation – but police yesterday were still unraveling why he turned violent after working at the agency for 29 years, his entire adult life.

He shot Benjamin Mwangi, 37, a maintenance foreman, who died at the scene, and Michael Stevenson, 55, a mechanic, who was taken to University of California San Diego Medical Center. Stevenson was placed on life-support and died at 3 p.m., the Medical Examiner's Office said.

Glasco, a revenue technician who serviced fare boxes, had just finished a 6 p.m. to 2 a.m. shift at the facility at Imperial Avenue and 16th Street in East Village when the shootings occurred.

After he left the employee lounge, witnesses heard two shots. Then, moments later, more shots. The employees ran.

Police were called and found Glasco in the parking lot. He still had the gun in his hand. Officers ordered him to drop it. Glasco made a call on his cell phone, then pointed the gun at the officers, police said. Three of them opened fire, and Glasco was killed.

Mwangi had worked for MTS since 2007, after a job with National City Transit. He also owned Mwangi Smog Test in Spring Valley, where his sole employee called him “a good guy, a good father.”

“He was always a real cool guy with me,” said Diego Delgado, who added that Mwangi hired him because it was too exhausting working the graveyard shift at MTS while running the smog test shop. “He'd even give me bonuses for doing stuff around here. I'm in shock.”

Mwangi grew up in Muranga in south-central Kenya, his family said. He moved to the United States about 13 years ago, and met and married his wife, Mary-Spring, three years later. The couple, parents to daughter Kozette, 8, and Mary-Spring's daughter, Kylie, 17, had planned to renew their marriage vows on their 10th anniversary, April 24.

A family friend, Diane Moses, called Benjamin Mwangi “kind, caring and willing to help you out in time of need.”

Stevenson was found in an MTS office near the service bays. He was from San Diego and had been with the transit agency for 31 years.

Further information on Stevenson was unavailable last night.

“This has been a tragic day for the victims of this incident, and for their families and friends,” Paul Jablonski, chief executive officer of MTS, said in a statement. “Our hearts and prayers go out to them.”

About 10 other people were working at the yard when the shooting happened. Grief counselors are offering group and individual sessions at the transit agency.